Maksutov telescope

A type of catadioptric telescope
(an instrument combining mirrors and lenses), developed by the Russian optical
specialist Dmitri Maksutov (1896-1964). It uses a spheroidal primary mirror,
a deeply-curved spheroidal meniscus corrector
plate, and a small spheroidal secondary mirror fixed to, or simply silvered
on to, the back of the corrector plate, to give a triple-folded optical
path. The result is a very compact telescope of long focal
length that gives a wide field of
view and images of excellent quality. Well-made "Maks" outperform Schmidt-Cassegrain
telescopes of equal quality and have became popular with amateur astronomers,
especially for astrophotography and planetary viewing. However, because
their corrector plates are difficult to manufacture for large aperture
instruments, their professional application is limited.